Development of the Nonstationary Incremental Analysis Update Algorithm for Sequential Data Assimilation System

Figure 6

(a) Probability distribution function (PDF) of the deviation of the high-frequency (i.e., higher than 1.5 hours) power in each method (the EKF, the IAU, the NIAU, and the NIAU with the reconstructed TLM) from that of the true state, normalized by the high-frequency power of truth. The lower and upper end of the bar denote 15% and 85% of the cumulative distribution function, respectively, with the median denoted as a line crossing the bar. The numbers in the -axis denote the number of SVs used to reconstruct the TLM for the calculation of the NIAU increment. (b) denotes the time average (from day 0 to day 10) RMSE in the EKF, the IAU, the NIAU, and the NIAU with the reconstructed TLM.

(a)

(b)